Electrochemical cells for use in automatic dishwashing appliances are designed to operate by making use of the water electrolysis process wherein, at the anode-water interface, OH− being present in water due to electrolytic dissociation of water molecules donates an electron to the anode and can be thereby oxidized to oxygen gas which can be removed from the system. As a result, the H+ concentration can be enhanced at the anode-water interface so that H+ enriched acidic water can be produced. In a similar manner, at the cathode-water interface, H+ accepts an electron from the cathode and can be reduced to hydrogen to form hydrogen gas which can be similarly eliminated from the system so that the OH− concentration can be increased at the cathode-water interface whereby OH− enriched alkaline water can be generated. Further, when halogen ion containing water (such as, natural water containing sodium chloride or an aqueous solution of sodium chloride) is subjected to electrolysis, halogenated mixed oxidants are generated in the electrolyzed water.
The following references disclose use of electrochemical cells: U.S. Pat. Nos. 5,932,171; 4,481,086; 4,434,629; 4,493,760; 4,402,197; 5,250,160; 5,534,120; 5,865,966; 5,947,135; JP Application No. 10057297A; JP Application No. 10179489A; JP Application No. 10033448A; JP Patent No. 09122060; JP Patent No. 2000116587; JP Patent No. 10178491; and EP Application No. 0983806A1.
The following references are also related to electrolyzed water: U.S. Pat. Nos. 3,616,355; 4,048,047; 4,062,754; 4,100,052; 4,328,084; 4,761,208; 5,314,589; 5,395,492; 5,439,576; 5,954,939 (equiv. EP 711,730); and WO 00/34184.
U.S. Pat. No. 4,402,197 encompasses in-line generation of hypochlorite from saline using an attached, non-partitioned electrochemical cell. U.S. Pat. No. 5,534,120 describes an attached, non-partitioned electrochemical cell, which can optionally separate the acidic/alkaline ionized water streams separately in the treatment of dishware. U.S. Pat. No. 5,947,135 describes the use of an attached, partitioned electrochemical cell that produces separate anolyte/catholyte streams for cleaning and disinfection of tableware. JP Application No. 10033448A discloses the use of an attached electrochemical cell in conjunction with an alkaline cleaning agent containing enzymes to clean tableware.
A problem with using attached electrochemical cells in automatic dishwashers can be that the electrochemical cells eventually become fouled from scaling and no longer function efficiently which can be difficult to remedy. Several remedies have been proposed. For example, JP Application No. 10057297A and U.S. Pat. No. 5,954,939 reduce scale formation in the electrochemical cell by electrode polarity reversal. WO Patent Number 00/64325 and U.S. Pat. No. 4,434,629 incorporate the electrochemical cell as part of a water softening system to reduce scaling. U.S. Pat. No. 5,932,171 provides an electrode cleaning composition, such as a source of acid or other descaler, to purge the electrochemical cell. Such remedies to descaling of attached electrochemical cells in automatic dishwashing appliances in the above references can increase the manufacturing cost of the appliance (e.g. polarity reversal, water softeners) or are inconvenient, temporary fixes (e.g. cleaning solutions) that require regular consumer attention.
Another problem of attached electrochemical cells can be that consumers should buy brand new, often expensive, automatic dishwashing appliances to experience the benefits of using electrolyzed water. It has now surprisingly been found that the use of an unattached electrolytic device, comprising an electrochemical cell, offers an efficient and convenient alternative to the abovementioned problem. In this case, either the unattached electrolytic device itself or its replaceable components can be exchanged for new. For instance, a consumer can decide to replace the disposable electrochemical cell in the unattached electrolytic device. If the consumer later desires to replace the unattached electrolytic device itself, this can also be done. This can be especially advantageous in automatic dishwashing appliances where consumer convenience can be desired.
Furthermore, the unattached devices of the present invention can be used with existing residential and commercial automatic dishwashing appliances, allowing consumers to experience the benefits of electrolyzed water in their current appliance without having to upgrade.